1. Field of the Invention
This invention relates to apparatus for cutting openings in the wall of a pipe of cuttable material, in particular plastics drainage pipes, the outer periphery of the wall of the pipe having transverse corrugations.
2. Description of the Prior Art
A known apparatus of this kind comprises at least one cutter head having ridges for engaging in the transverse corrugations of the pipe, at least one cutter mounted on the cutter head, planetary gear means for positively driving the cutter head so that it rolls at least in part on the outer periphery of the pipe and the cutting edge of the cutter moves around the pipe on an epitrochoidal path, at least one support roller for abutting the pipe wall to take up thrust forces and mounting means for the support roller.
Apparatus of this kind known from U.S. Pat. No. 3,824,886 has in practice proved to be very effective, since it makes possible continuous cutting of openings in corrugated pipes and even the cutting of openings in each corrugation valley, the chip cut-out from the outer wall of the pipe being cut out towards the exterior on account of the travel of the cutting edge of each cutter on an epitrochoid and not therefore falling into the pipe. The known apparatus is however deserving of improvement in regard to its use for special forms of pipes, such as for example, pipes having annular corrugations, which in addition can have a foot not to be provided with openings.